Abstract: This study utilizes a mixed cross-sectional dataset synthesized from the CHARLS and CGSS databases and employs a two-way fixed effects model to explore the roles of neighbors and relatives as two informal entities in home-based elderly care services and their differential performances in urban and rural areas. The findings reveal: (1) the effectiveness of informal support in home-based elderly care services is limited, particularly in enhancing the psychological well-being and social participation of the elderly; (2) neighbor care plays a significant role in promoting the social participation of the elderly, especially in rural areas, where its effect surpasses that of relative care; (3) there are differences in the roles of relatives and neighbors in urban and rural elderly care services. In urban areas, neighbor care is more prominent, while in rural areas, relative care remains irreplaceable. Based on these findings, it is imperative to build a comprehensive elderly care service system that integrates informal and formal support, strengthen the skill training of informal caregivers to improve service quality, innovate the elderly care service model with a "entity + technology" approach, balance the allocation of elderly care resources between urban and rural areas, and narrow the gap in elderly care services between urban and rural areas.